China’s internet giants Alibaba and Tencent have been focusing on this region of over 600 million consumers as their home market slows.

If the deal closes, it would make Grab a key player in the Alibaba group’s proxy war with Tencent – maker of popular messaging app WeChat. It will allow Ma’s Ant Financial to further market its digital payment service Alipay to riders in the region, as Tencent supposedly joins forces with Grab’s Indonesian rival, Go-Jek. Grab has an ongoing tie-up with Ant Financial for the use of Alipay, while Go-Jek in the past year has been developing a fully fledged mobile payments platform.

The US$1.5 billion financing, which will surpass Grab’s previous US$750 million fundraise, could be a record for Southeast Asia.